Abstract
Although empathic responses to stimuli with emotional contents may occur automatically, humans are capable to intentionally empathize with other individuals. Intentional empathy for others is even possible when they do not show emotional expressions. However, little is known about the neuronal mechanisms of this intentionally controlled empathic process. To investigate the neuronal substrates underlying intentional empathy, we scanned 20 healthy Chinese subjects, using fMRI, when they tried to feel inside the emotional states of neutral or angry faces of familiar (Asian) and unfamiliar (Caucasian) models. Skin color evaluation of the same stimuli served as a control task. Compared to a baseline condition, the empathy task revealed a network of established empathy regions, including the anterior cingulate cortex, bilateral inferior frontal cortex and bilateral anterior insula. The contrast of intentional empathy vs skin color evaluation, however, revealed three regions: the bilateral inferior frontal cortex, whose hemodynamic responses were independent of perceived emotion and familiarity and the right-middle temporal gyrus, whose activity was modulated by emotion but not by familiarity. These findings extend our understanding of the role of the inferior frontal cortex and the middle temporal gyrus in empathy by demonstrating their involvement in intentional empathy.
Keywords: fMRI, brain imaging, empathy
INTRODUCTION
Empathy describes our ability to understand and share the emotional states of others (Batson et al., 1987; Decety and Jackson, 2004; Blair, 2005). This ability is of striking importance for our survival and success in social environments (Blair, 2003; Gallese et al., 2004). Empathy consists of various mechanisms, which can be dissociated psychologically and neuroscientifically (Preston and de Waal, 2002; Blair, 2005). At this, most empathic responses to emotional cues in perceived stimuli, such as facial expressions, occur automatically (Dimberg and Thunberg, 1998; Chartrand and Bargh, 1999; Dimberg et al., 2000; Han et al., 2008; Kramer et al., 2010). Humans, however, are capable to voluntarily focus their empathy on others (Nummenmaa et al., 2008). This intentionally controlled empathy may even occur when no salient emotional cues are available in the perceived stimuli and is dissociated from the automatic empathy processes in time course (Fan and Han, 2008).
Most of the previous studies identified neural substrates underlying emotional empathy by comparing stimuli with different emotional intensities (Breiter et al., 1996; Morris, et al., 1996; Phillips et al., 1997; Sprengelmeyer et al., 1998; Blair et al., 1999), by comparing the perception of emotions and the observation of others experiencing the same emotions (Wicker et al., 2003; Jabbi et al., 2007; Jabbi and Keysers, 2008), or by comparing the perception of emotions with the imitation of the same emotions (Carr et al., 2003).While these studies found neural activity in brain areas such as the anterior cingulate (ACC), anterior insula, superior temporal cortex, amygdala and inferior frontal cortex (Breiter et al., 1996; Morris et al., 1996; Phillips et al., 1997; Sprengelmeyer et al., 1998; Blair et al., 1999; Carr et al., 2003; Wicker et al., 2003; Jabbi et al., 2007), the designs employed in the previous work did not allow to isolate intentionally controlled processes from automatically generated processes of empathy. In addition, although a number of studies investigated the modulation of ‘empathy for pain’ by cognitive mechanisms (Lamm et al., 2007a, b; Hein and Singer, 2008) or experience to painful practices (Cheng et al., 2007), the neuronal basis underlying the cognitive modulation of ‘emotional empathy’ has, to our knowledge, not been investigated so far.
The first aim of our study was to uncover the neural mechanisms underlying intentionally controlled processes involved in emotional empathy. To differentiate between intentional empathy and automatic empathic responses, we applied a visual fMRI paradigm that included two tasks. An intentional empathy task asked subjects to actively share the emotional state of perceived faces with angry and neutral expressions. Automatic emotional responses may particularly be triggered by the presence of emotional cues in the presented stimuli. It may hence be difficult to completely disentangle intentionally generated and automatic empathic processes in emotional stimuli. The application of facial stimuli showing neutral emotional expressions (Nomi et al., 2008; Nummenmaa et al., 2008) reduces the automatic empathic responses and thus may help to uncover the intentional empathy. A second task asked subjects to evaluate the skin color of the same face stimuli. The first task required understanding and sharing the emotion of faces and thus tackled the intentional process involved in empathy. The second task created a control condition in which subjects concentrated on the facial stimuli alike the first task and were able to generate an automatic emotional response, however, without an intentional empathy component. In addition, the skin color evaluation task controlled for the processing of perceptual features of face stimuli and motor responses.
Which brain regions did we expect to be involved in intentional empathy? Considering the different empathy concepts, the paradigm used in the current study is similar to the tasks previously applied to investigate emotional mentalizing (Ochsner et al., 2004; Hooker et al., 2008, 2010). Hence, we expected to find the superior temporal sulcus, medial prefrontal cortex, the temporal poles and the inferior frontal cortex to be activated during intentional empathy, since these areas were involved in emotional mentalizing (Ochsner et al., 2004; Hooker et al., 2008, 2010).
The second aim of our study was to investigate whether the brain regions involved in intentional empathy are modulated by emotion cues in the stimuli. Two alternative mechanisms are thinkable: a brain region involved in intentional empathy may activate completely independently from the presence or absence of emotion in perceived facial stimuli. If this is the case, we should consider this region as responsible for genuine intentional empathy. It may be, however, that neuronal activity of a brain region is modulated by the presence or absence of emotion. Then we would suggest that this brain region is not completely responsible of intentional empathy, but rather modulated by intentional empathy. In order to explore this effect, we applied emotional (angry) and neutral facial stimuli in the empathy task.
The third aim of our study was to investigate a potential effect of familiarity with target persons on intentional empathy. As recently shown by a number of studies, race-based familiarity is an effective modulator of empathy for pain (Xu et al., 2009; Avenanti et al., 2010; Chiao and Mathur, 2010; Mathur et al., 2010). The effects of race-based familiarity on intentional empathy have, however, not been investigated, so far. In order to test for a potential effect of race-based familiarity on intentional emotional empathy, we applied neutral stimuli of familiar (Asian) and unfamiliar (Caucasian) faces to Chinese subjects.
METHODS
Subjects
We investigated 20 healthy Chinese subjects (11 female, 9 male, mean age: 23, range: 21–26 years). After a detailed explanation of the study design and any potential risks, all subjects gave their written informed consent. All of the subjects were Chinese college students. The study was approved by a local ethics committee at the Department of Psychology, Peking University.
Paradigm
Experimental design
The fMRI experiment was divided into seven blocks of 312 s duration each. Prior to entering the scanner, each subject read detailed information of the paradigm and completed a couple of trial runs in order to familiarize fully with the task. While lying in the scanner, the stimuli were displayed using the software package ‘Presentation’ (Neurobehavioral Systems, Albany, CA, USA), and were projected onto a matt screen via an LCD projector, visible through a mirror mounted on the head coil.
Every block started with 10-s pause to control for epi-saturation effects. A total number of 24 trials (12 intentional empathy trials and 12 trials skin color evaluation trials) were presented in a randomized order in each block. Figure 1 illustrates the intentional empathy task and the control task. After every six trials a baseline trial was included, which consisted of the mere presentation of the fixation cross, lasting for 6 or 7 s.
Stimuli
Our emotional face stimuli consisted of 12 different faces. Each of the three conditions, namely familiar angry, familiar neutral and unfamiliar neutral, contained four different faces (two female and two male). The four stimuli of the unfamiliar neutral condition were taken from the ‘Japanese and Caucasian Facial Expressions of Emotion (JACFEE) and Neutral Faces (JACNeuF)’-battery provided by Matsumoto and Ekman (Matsumuto and Ekman, 1988). The eight stimuli of the familiar angry and familiar neutral condition were photographed and preprocessed for presentation by our own group. These pictures were taken in front of a comparable background and under comparable conditions to match them as close as possible to the four pictures taken from the JACNeuF battery. Every stimulus was presented twice during each block: once during intentional empathy, once during skin color evaluation.
Behavioural tests
We applied the ‘Interpersonal Reactivity Index’ (IRI; Davis, 1983) to measure individual empathic characteristics of our subjects. The IRI is a commonly used self evaluation questionnaire (Kaplan and Iacoboni, 2006), which is apt to state the subjective impression of different empathic skills. The IRI uses four subscales related to perspective taking, empathic fantasy, empathic concern and empathic personal distress.
Behavioural data analysis
The subjects’ performance and reaction times for intentional empathy and skin color evaluation trials were compared using paired t-tests.
fMRI data acquisition
The study was conducted using a General Electrics 3 Tesla Magnetic Resonance Imaging Scanner (24 slices parallel to the AC-PC plane, slice thickness 5 mm, TR 2000 ms, TE 30 ms, flip angle α = 90°, 64 × 64 voxels per slice with 3.75 × 3.75 × 5 mm). Functional data were acquired in seven scanning sessions containing 156 volumes per session for each subject.
fMRI data analysis
The statistical analysis of the fMRI data was performed using the SPM2 software package (SPM2, http://www.fil.ion.ucl.ac.uk) and Matlab 6.5.1 (The Mathworks Inc., Natick, MA, USA). fMRI data were slice time corrected with regard to the first slice acquired and movement corrected by realignment to the first volume. Subjects’ T1-weighted anatomical images were coregistered to their first functional image. All functional images were normalized to a standard T1-weighted SPM template (Ashburner and Friston, 1999). The normalization was generated by warping the subject’s coregistered anatomical image to the T1-weighted SPM template followed by the application of the same normalization parameters to the functional images. Smoothing was performed using an 8 × 8 × 8 mm full-width half-maximum Gaussian kernel.
A statistical model for each subject was computed by applying a canonical response function (Friston et al., 1998). All relevant periods (namely the viewing and evaluation periods for all emotions and both tasks, as well as viewing and evaluation periods for trials without confirmed responses, and the baseline event) were included in the SPM model. Regionally, specific condition effects were tested by employing linear contrasts for each subject and different conditions. The resulting contrast images were submitted to a second-level random-effects analysis. Here, one-sample t-tests were used on images obtained for each subject’s volume set and different conditions. To control for the multiple testing problem, we performed a false discovery rate correction (Nichols and Hayasaka, 2003). The anatomical localization of significant activations was assessed with reference to the standard stereotactic atlas and by superimposition of the SPM maps on a mean brain generated by averaging of each subject’s T1-weighted image.
In a second step, we analysed the fMRI raw data using the Marseille Region of Interest Toolbox software package [(Brett et al., 2002), MarsBaR 1.86, http://www.sourceforge.net/projects/marsbar]. Using a sphere-shaped ‘region of interest’ (ROI, radius 5 mm), we extracted the raw data from activations found in the second-level analysis. fMRI raw data timecourses were processed using the software package PERL (http://www.perl.org). The timecourses were linearly interpolated and normalized with respect to a time window ranging from −6 to 30 s before and after the onset of each event. fMRI signal changes of every event were calculated with regard to the fMRI signal value of 0 s. Mean normalized fMRI signal values from two following time steps (6 and 8 s after onset of the viewing period) were included in the statistical analysis. We used paired t-tests to analyse the effect of the different emotion conditions on the fMRI raw data.
RESULTS
Behavioural results
Intra-scanner ratings
We did not find any significant differences between intentional empathy trials and skin color evaluation trials with regard to performance (Figure 2A) and reaction times of the first response (Figure 2B). However, we detected significant faster confirmation responses during intentional empathy when compared to skin color evaluation trials (Figure 2B). In addition, we found significant differences with regard to the subjective impression of empathy capability for the different conditions (Figure 2C).
Results of the IRI
Mean scores of our subjects for the different IRI subcategories were: empathic fantasy: 18.0 (95% CI: 15.6–20.4), empathic concern: 18.5 (95% CI: 17.2–19.8), perspective taking: 18.5 (95% CI: 17.2–19.8) and empathic distress 12.6 (95% CI: 11.3–13.9).
fMRI results
SPM contrast [intentional empathy] > [baseline]
This contrast revealed a number of brain regions commonly associated to the empathy network, including the inferior frontal cortex, anterior cingulate cortex, the supplementary motor area, the anterior insula and others (see Table 1 for details).
Table 1.
Region | x, y, z (mm)a | T | P[FDR] |
---|---|---|---|
Left Inferior frontal cortex | −48, 2, 43 | 5.88 | 0.001 |
Right Inferior frontal cortex | 50, 6, 24 | 5.18 | 0.002 |
48, 6, 32 | 5.11 | 0.002 | |
40, 30, 14 | 3.67 | 0.020 | |
Left Prefrontal cortex | −36, 50, 16 | 3.40 | 0.030 |
−35, 40, 10 | 3.39 | 0.030 | |
Left Anterior cingulate cortex | −6, 0, 54 | 6.35 | <0.001 |
Right Anterior cingulate cortex | 10, 8, 48 | 6.50 | <0.001 |
Left Supplementary motor area | −26, −10, 54 | 7.04 | <0.001 |
Right Supplementary motor area | 26, −4, 60 | 4.38 | 0.007 |
38, −14, 56 | 3.52 | 0.025 | |
Left Anterior insula | −30, 22, 4 | 4.90 | 0.003 |
Right Anterior insula | 32, 22, 6 | 4.08 | 0.010 |
Left Putamen | −22, 4, 4 | 4.89 | 0.003 |
Right Putamen | 22, 6, 6 | 4.10 | 0.010 |
Left Posterior parietal cortex | −10, −76, 50 | 4.17 | 0.009 |
−22, −72, 40 | 3.16 | 0.042 | |
−32, −50, 36 | 3.81 | 0.016 | |
−28, −66, 52 | 3.14 | 0.044 | |
Left Occipital cortex | −14, −96, −8 | 10.47 | <0.001 |
−40, −70, −28 | 9.17 | <0.001 | |
−34, −76, −28 | 8.44 | <0.001 | |
Right Occipital cortex | 28, −88, −8 | 11.62 | <0.001 |
24, −84, −15 | 11.08 | <0.001 | |
36, −62, −24 | 8.93 | <0.001 |
The contrast was calculated using an FDR correction for multiple comparisons. The table contains all clusters with P[FDR] < 0.05 and a minimum cluster size of 10 voxels (n = 20).
aCoordinates refer to the MNI stereotactic space.
SPM contrast [intentional empathy] > [skin color evaluation]
This contrast revealed three regions associated with intentional empathy: the left and right inferior frontal cortex and the right middle temporal gyrus (Table 2 and Figure 3). The opposite contrast [skin color evaluation] > [intentional empathy] showed no regions activated above the threshold of P[uncorrected] ≤ 0.001.
Table 2.
Region | x, y, z (mm)a | T | P[uncorrected] |
---|---|---|---|
Left Inferior frontal cortex | −48, 22, −2 | 4.66 | <0.001 |
Right Inferior frontal cortex | 48, 28, 4 | 4.66 | <0.001 |
Right Middle temporal gyrus | 62, −54, 0 | 3.98 | <0.001 |
This contrast (n = 20, uncorrected threshold 0.001, minimum cluster size 10 voxels) revealed three regions with stronger hemodynamic responses during intentional empathy: the bilateral inferior frontal cortex and the right middle temporal gyrus. The opposite contrast [skin color evaluation] > [intentional empathy] did not reveal any significant regions under the same threshold conditions.
aCoordinates refer to the MNI stereotactic space.
Analyses of fMRI raw data
The results of the fMRI raw data analysis are presented in Figure 3.
SPM contrasts for the different emotion conditions
Using SPM one sample t-tests, we looked for regions with different hemodynamic responses during the intentional empathy subconditions (namely familiar angry, familiar neutral and unfamiliar neutral). Applying a threshold of P[uncorrected] < 0.001 and a minimum cluster size of 10 voxels, we did not find regions with differences in hemodynamic responses during the presentation of familiar angry and familiar neutral faces. Using the same threshold, we did not find any areas with different hemodynamic responses during familiar neutral faces and unfamiliar neutral faces.
SPM contrast [familiar neutral] > [unfamiliar neutral]
In addition, we used an SPM one sample t-test, to look for regions with different hemodynamic responses during the perception (intentional empathy + skin color evaluation) of familiar neutral and unfamiliar neutral faces. Applying a threshold of P[uncorrected] < 0.001 and a minimum cluster size of 10 voxels, we did not find any cluster for the contrast [familiar neutral] > [unfamiliar neutral]. In addition, we did not find any activations in the opposite contrast [unfamiliar neutral] > [familiar neutral] using the same threshold criteria.
SPM correlations using mean empathy ratings and IRI scores
We performed a supplementary SPM analysis, in which we introduced behavioural variables into simple SPM correlations using the images of the contrast [intentional empathy] > [skin color evaluation]. Looking for regions in which each subject’s mean intra-scanner empathy rating predicted their contrast value of the contrast [intentional empathy] > [skin color evaluation], the SPM correlation revealed only one region, the left-posterior fusiform gyrus [−34, −82, −20, t(18) = 3.87, P[uncorrected] < 0.001, minimum cluster size 10 voxels, Figure 4].
Correlating the same contrast images with each subjects mean IRI score for empathic fantasy, empathic concern, perspective taking and empathic distress, we found no significant voxels above the rational threshold of P[uncorrected] < 0.001 and a minimum cluster size of 10 voxels.
DISCUSSION
Relative to the baseline condition, the intentional empathy task increased activity in a neural circuit consisting of the inferior frontal cortex, anterior cingulate cortex, the supplementary motor area and the anterior insula. This is consistent with the observation of previous studies of empathy (Breiter et al., 1996; Morris et al., 1996; Phillips et al., 1997; Sprengelmeyer et al., 1998; Blair et al., 1999; Carr et al., 2003; Wicker et al., 2003; Jabbi et al., 2007). However, compared to the control condition that required skin color evaluation, the intentional empathy task induced significant stronger hemodynamic responses in the bilateral inferior frontal cortex and the right middle temporal gyrus, revealing brain regions specifically involved in intentional empathy. Looking for effects of emotion, we found only the right middle temporal gyrus with stronger hemodynamic responses during intentional empathy for familiar angry faces compared to familiar neutral faces. None of the regions showed evidence for modulations by the race-based familiarity between the observed and target person. Hemodynamic responses during skin color evaluation of the left inferior frontal cortex and the right middle temporal gyrus showed a tendency for an emotional effect, with stronger hemodynamic responses during familiar angry faces, compared to familiar neutral faces. Again, we did not find any modulation of hemodynamic responses caused by race-based familiarity. Differences in hemodynamic responses between intentional empathy and skin color evaluation of the left fusiform gyrus correlated with mean intra-scanner empathy ratings.
The inferior frontal cortex and middle temporal gyrus have been shown to be involved in emotional empathy (Blair et al., 1999; Carr et al., 2003; Decety and Chaminade, 2003; Chakrabarti et al., 2006; Jabbi et al., 2007). Our fMRI results indicate that these brain areas engage in intentional empathy for other individuals even when no perceived emotional cues are available. In other words, the neuronal activity of left and right inferior frontal cortex during intentional empathy was independent of the emotional content of the stimuli. This finding demonstrates that neuronal activity in the bilateral inferior frontal cortex can be exclusively internally generated, without any modulation by the external emotional cues. Hemodynamic responses of the right middle temporal gyrus, however, were modulated by the emotional content of the presented pictures, indicating that neuronal activity of this region is not exclusively internally generated.
Our findings extend our understanding of the role of the inferior frontal cortex in empathy. The inferior frontal cortex is known to be part of the human mirror neuron system, a network of brain regions which are involved in the generation of actions as well as in the perception of actions performed by others (Iacoboni et al., 1999; Carr et al., 2003; Grezes et al., 2003; Iacoboni, 2005; Iacoboni et al., 2005; Iacoboni and Dapretto, 2006; Kaplan and Iacoboni, 2006); at first, it was detected in the monkey (Gallese et al., 1996; Rizzolatti et al., 1996; Buccino et al., 2001; Rizzolatti et al., 2001; Ferrari et al., 2003; Rizzolatti and Craighero, 2004). A number of studies showed the involvement of the mirror neuron system and particularly the inferior frontal cortex in empathic processes such as emotional empathy (Kaplan and Iacoboni, 2006), emotional imitation (Carr et al., 2003; Lee et al., 2006), passive emotion perception (Chakrabarti et al., 2006) and emotion evaluation (Decety and Chaminade, 2003). Since these studies used emotional stimuli, the observed inferior frontal activity may mainly subserve emotion regulation. In our work, however, the observed inferior frontal activity observed mainly reflects intentional control of emotional empathy, since it was detected in a task requiring empathy for neutral faces. This task reduced emotional responses to a minimum degree and thus did not require emotion regulation. Interestingly enough, two studies reported the inferior frontal cortex to be involved in intentional emotion imitation (Carr et al., 2003; Lee et al., 2006). Our study contributes to these findings in showing that the mere intentional emotional sharing of another’s state is sufficient to activate the inferior frontal cortex—even without emotions expressed by the target.
In addition, the right middle temporal gyrus (as part of the posterior superior temporal sulcus region) showed stronger hemodynamic responses during intentional empathy when compared to the control task. These results complement previous findings which described the involvement of the superior temporal sulcus region in several emotional tasks. Activation of the superior temporal sulcus region was often found together with co-activation of the inferior frontal cortex during the same contrasts (Carr et al., 2003; Grezes et al., 2003; Chakrabarti et al., 2006; Hoekert et al., 2008; Hooker et al., 2008, 2010). Additional papers suggest nevertheless that the superior temporal sulcus region is comparatively more involved in social cognitive tasks, such as the passive perception of social scenes (Kramer et al., 2010) or Theory of Mind (Vollm et al., 2006). In their review paper, Allison and colleagues (Allison et al., 2000) suggest that the superior temporal sulcus region is ‘sensitive to stimuli that signal the actions of another individual’. Interestingly, and in contrast to the inferior frontal cortex, the right middle temporal gyrus showed a significant modulation by emotion with stronger hemodynamic responses during familiar angry faces compared to familiar neutral faces. This finding can perhaps be explained by the assumption that angry facial expression are comparatively more salient to neutral ones and imply greater social relevance (Blair, 2005).
None of the three regions involved in intentional empathy observed in our study was affected by familiarity. Recently, a number of studies found race-based familiarity to be an effective modulator of brain activity related to empathy for pain. Regions modulated by race-based familiarity included the anterior cingulate cortex (Xu et al., 2009; Mathur et al., 2010), the insula (Mathur et al., 2010) and the sensorimotor system (Avenanti et al., 2010). In addition, differences in activity of the fusiform gyrus during the memorizing of facial stimuli of the same race (African-American) and another race (Caucasian) were reported (Golby et al., 2001) as well as differences in the activity of the amygdala, the superior temporal cortex and other regions during very short presentations of other race (African-American) and same race (Caucasian) facial stimuli (Cunningham et al., 2004). However, none of these studies reported differences of inferior frontal cortex activity related to race-based differences in familiarity. Moreover, none of these studies investigated intentional emotional empathy. Together these results suggest that the social relation between an observer and a target mainly modulates the automatic processes of empathy. The intentionally controlled process of empathy mediated by the inferior frontal cortex, however, seems to function independently of the social relation between the observer and a target. These findings provide additional evidence for the dissociation between intentionally controlled processes from the automatically generated processes of empathy.
The voxel-based correlation analysis revealed a significant correlation of neuronal activity in the left posterior fusiform gyrus with subjective empathy ratings. This brain area is located posterior to the fusiform face area that is crucially involved in the processing of faces (Kanwisher et al., 1997; Grill-Spector et al., 2004; Iidaka et al., 2006; Fusar-Poli et al., 2009). The posterior fusiform region observed in our study seems nonetheless to overlap with regions observed in the processing of emotional faces (Geday et al., 2003; Etkin et al., 2004; Nomi et al., 2008) and empathy with painful emotional faces (Lamm et al., 2007a). The here observed correlation of hemodynamic modulation in the posterior fusiform gyrus and mean empathy ratings might hence be interpreted as increased processing of the facial stimuli in those subjects, which gave overall higher empathy ratings.
A few limitations of our study should be noted. First, during both tasks we were not able to control on which specific aspect of the facial stimuli our subjects focused. It might be that during the intentional empathy task subjects focused more on the eyes of the facial stimuli, while subjects possibly concentrated on the cheeks and the forehead during the skin color perception task. Second, as demonstrated in Figure 3, the contrast between the intentional empathy task and the skin color evaluation task was mainly shaped by the distinct negative signal changes during the skin color evaluation task, rather than by the positive hemodynamic responses during intentional empathy. We are puzzled by this finding and can only provide a rather speculative explanation that awaits further research. It may be the case that the pronounced negative fMRI signal changes during skin color evaluation reflect the intentionally controlled inhibition of empathy processes. In other words, neuronal activity of the bilateral inferior frontal cortex and superior temporal sulcus region may be not so much affected by the intentionally controlled generation of empathy, but rather by its intentionally controlled inhibition. Third, the variety of emotions applied in our paradigm is rather low (only angry and neutral). Future studies may investigate intentional empathy with other emotions. In addition, it might be interesting for future studies to examine whether the influence of race-based familiarity on empathy is modulated by different emotions of perceived facial expressions.
CONCLUSIONS
Our results underline the important role of the bilateral inferior frontal cortex and the right superior temporal sulcus region in empathy. We were able to show that these regions play a pivotal role in intentional empathy. Hemodynamic responses of bilateral inferior frontal cortex during intentional empathy were only modulated by the task, whereas the right superior temporal sulcus region was affected by the emotional content of the facial stimuli. None of the three regions showed an effect of the race-based familiarity of perceived stimuli. Our findings suggest that the inferior frontal activity underlying intentionally controlled empathic responses is independent of both emotional contents in perceived stimuli and familiarity between the observer and target person.
Acknowledgments
The authors thank Yan Fan, Zhenhao Shi and Yina Ma for their help in the preparation of the stimuli. We further thank for the support by Claus Tempelmann and the staff of the Department of Neurology of the Otto-von-Guericke-University of Magdeburg in the acquisition of pilot data. We also thank Niall Duncan for helpful propositions to the script. Financially, this study was supported by the Science and Technology Fellowship Programme in China (STFP-25 to M.G.). We are also indebted to the German research Foundation (DFG-SFB 779-A6), the Hope of Depression Research Foundation (HDRF), the CRC and the EJLB Michael Smith Foundation for providing generous financial support (to G.N.), and to the National Natural Science Foundation of China (Project 30630025, 30828012, 30910103901), the National Basic Research Program of China (973 Program 2010CB833903), and the Fundamental Research Funds for the Central Universities (providing generous financial support to S.H.).
REFERENCES
- Allison T, Puce A, McCarthy G. Social perception from visual cues: role of the STS region. Trends in Cognitive Science. 2000;4:267–78. doi: 10.1016/s1364-6613(00)01501-1. [DOI] [PubMed] [Google Scholar]
- Ashburner J, Friston KJ. Nonlinear spatial normalization using basis functions. Human Brain Mapping. 1999;7:254–66. doi: 10.1002/(SICI)1097-0193(1999)7:4<254::AID-HBM4>3.0.CO;2-G. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Avenanti A, Sirigu A, Aglioti SM. Racial bias reduces empathic sensorimotor resonance with other-race pain. Current Biology. 2010;20:1018–22. doi: 10.1016/j.cub.2010.03.071. [DOI] [PubMed] [Google Scholar]
- Batson CD, Fultz J, Schoenrade PA. Distress and empathy: two qualitatively distinct vicarious emotions with different motivational consequences. Journal of Personality. 1987;55:19–39. doi: 10.1111/j.1467-6494.1987.tb00426.x. [DOI] [PubMed] [Google Scholar]
- Blair RJ. Facial expressions, their communicatory functions and neuro-cognitive substrates. Philosophical transactions of the Royal Society of London. Series B, Biological sciences. 2003;358:561–72. doi: 10.1098/rstb.2002.1220. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Blair RJ. Responding to the emotions of others: dissociating forms of empathy through the study of typical and psychiatric populations. Consciousness and cognition. 2005;14:698–718. doi: 10.1016/j.concog.2005.06.004. [DOI] [PubMed] [Google Scholar]
- Blair RJ, Morris JS, Frith CD, Perrett DI, Dolan RJ. Dissociable neural responses to facial expressions of sadness and anger. Brain. 1999;122:883–93. doi: 10.1093/brain/122.5.883. [DOI] [PubMed] [Google Scholar]
- Breiter HC, Etcoff NL, Whalen PJ, et al. Response and habituation of the human amygdala during visual processing of facial expression. Neuron. 1996;17:875–87. doi: 10.1016/s0896-6273(00)80219-6. [DOI] [PubMed] [Google Scholar]
- Brett M, Anton J-L, Valabregue R, Poline J-B. In Presented at the 8th International Conferance on functional Mapping of the Human Brain, June 26, 2002. Sendai, Japan: 2002. Region of interest analysis using an SPM toolbox [abstract] Available on CD-ROM in NeuroImage, Vol. 16, No. 2, abstract 497. [Google Scholar]
- Buccino G, Binkofski F, Fink GR, et al. Action observation activates premotor and parietal areas in a somatotopic manner: an fMRI study. European Journal of Neuroscience. 2001;13:400–4. [PubMed] [Google Scholar]
- Carr L, Iacoboni M, Dubeau MC, Mazziotta JC, Lenzi GL. Neural mechanisms of empathy in humans: a relay from neural systems for imitation to limbic areas. Proceedings of the National Academy of Sciences of the United States of America. 2003;100:5497–502. doi: 10.1073/pnas.0935845100. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chakrabarti B, Bullmore E, Baron-Cohen S. Empathizing with basic emotions: common and discrete neural substrates. Social Neuroscience. 2006;1:364–84. doi: 10.1080/17470910601041317. [DOI] [PubMed] [Google Scholar]
- Chartrand TL, Bargh JA. The chameleon effect: the perception-behavior link and social interaction. Journal of Personality and Social Psychology. 1999;76:893–910. doi: 10.1037//0022-3514.76.6.893. [DOI] [PubMed] [Google Scholar]
- Cheng Y, Lin CP, Liu HL, et al. Expertise modulates the perception of pain in others. Current Biology. 2007;17:1708–13. doi: 10.1016/j.cub.2007.09.020. [DOI] [PubMed] [Google Scholar]
- Chiao JY, Mathur VA. Intergroup empathy: how does race affect empathic neural responses? Current Biology. 2010;20:R478–80. doi: 10.1016/j.cub.2010.04.001. [DOI] [PubMed] [Google Scholar]
- Cunningham WA, Johnson MK, Raye CL, Chris Gatenby J, Gore JC, Banaji MR. Separable neural components in the processing of black and white faces. Psychological Science: A Journal of the American Psychological Society/APS. 2004;15:806–13. doi: 10.1111/j.0956-7976.2004.00760.x. [DOI] [PubMed] [Google Scholar]
- Davis MH. Measuring individual differences in empathy: evidence for a multidimensional approach. Journal of Personality and Social Psychology. 1983;44:14. [Google Scholar]
- Decety J, Chaminade T. Neural correlates of feeling sympathy. Neuropsychologia. 2003;41:127–38. doi: 10.1016/s0028-3932(02)00143-4. [DOI] [PubMed] [Google Scholar]
- Decety J, Jackson PL. The functional architecture of human empathy. Behavioral and Cognitive Neuroscience Reviews. 2004;3:71–100. doi: 10.1177/1534582304267187. [DOI] [PubMed] [Google Scholar]
- Dimberg U, Thunberg M. Rapid facial reactions to emotional facial expressions. Scandinavian Journal of Psychology. 1998;39:39–45. doi: 10.1111/1467-9450.00054. [DOI] [PubMed] [Google Scholar]
- Dimberg U, Thunberg M, Elmehed K. Unconscious facial reactions to emotional facial expressions. Psychological Sciences. 2000;11:86–9. doi: 10.1111/1467-9280.00221. [DOI] [PubMed] [Google Scholar]
- Etkin A, Klemenhagen KC, Dudman JT, et al. Individual differences in trait anxiety predict the response of the basolateral amygdala to unconsciously processed fearful faces. Neuron. 2004;44:1043–55. doi: 10.1016/j.neuron.2004.12.006. [DOI] [PubMed] [Google Scholar]
- Fan Y, Han S. Temporal dynamic of neural mechanisms involved in empathy for pain: an event-related brain potential study. Neuropsychologia. 2008;46:160–73. doi: 10.1016/j.neuropsychologia.2007.07.023. [DOI] [PubMed] [Google Scholar]
- Ferrari PF, Gallese V, Rizzolatti G, Fogassi L. Mirror neurons responding to the observation of ingestive and communicative mouth actions in the monkey ventral premotor cortex. European Journal of Neurosciences. 2003;17:1703–14. doi: 10.1046/j.1460-9568.2003.02601.x. [DOI] [PubMed] [Google Scholar]
- Friston KJ, Fletcher P, Josephs O, Holmes A, Rugg MD, Turner R. Event-related fMRI: characterizing differential responses. Neuroimage. 1998;7:30–40. doi: 10.1006/nimg.1997.0306. [DOI] [PubMed] [Google Scholar]
- Fusar-Poli P, Placentino A, Carletti F, et al. Functional atlas of emotional faces processing: a voxel-based meta-analysis of 105 functional magnetic resonance imaging studies. Journal of Psychiatry Neurosciences. 2009;34:418–32. [PMC free article] [PubMed] [Google Scholar]
- Gallese V, Fadiga L, Fogassi L, Rizzolatti G. Action recognition in the premotor cortex. Brain. 1996;119:593–609. doi: 10.1093/brain/119.2.593. [DOI] [PubMed] [Google Scholar]
- Gallese V, Keysers C, Rizzolatti G. A unifying view of the basis of social cognition. Trends in Cognitive Sciences. 2004;8:396–403. doi: 10.1016/j.tics.2004.07.002. [DOI] [PubMed] [Google Scholar]
- Geday J, Gjedde A, Boldsen AS, Kupers R. Emotional valence modulates activity in the posterior fusiform gyrus and inferior medial prefrontal cortex in social perception. Neuroimage. 2003;18:675–84. doi: 10.1016/s1053-8119(02)00038-1. [DOI] [PubMed] [Google Scholar]
- Golby AJ, Gabrieli JD, Chiao JY, Eberhardt JL. Differential responses in the fusiform region to same-race and other-race faces. Natural Neurosciences. 2001;4:845–50. doi: 10.1038/90565. [DOI] [PubMed] [Google Scholar]
- Grezes J, Armony JL, Rowe J, Passingham RE. Activations related to "mirror" and "canonical" neurones in the human brain: an fMRI study. Neuroimage. 2003;18:928–37. doi: 10.1016/s1053-8119(03)00042-9. [DOI] [PubMed] [Google Scholar]
- Grill-Spector K, Knouf N, Kanwisher N. The fusiform face area subserves face perception, not generic within-category identification. Natural Neurosciences. 2004;7:555–62. doi: 10.1038/nn1224. [DOI] [PubMed] [Google Scholar]
- Han S, Fan Y, Mao L. Gender difference in empathy for pain: an electrophysiological investigation. Brain Research. 2008;1196:85–93. doi: 10.1016/j.brainres.2007.12.062. [DOI] [PubMed] [Google Scholar]
- Hein G, Singer T. I feel how you feel but not always: the empathic brain and its modulation. Current Opinion in Neurobiology. 2008;18:153–8. [Google Scholar]
- Hoekert M, Bais L, Kahn RS, Aleman A. Time course of the involvement of the right anterior superior temporal gyrus and the right fronto-parietal operculum in emotional prosody perception. PLoS One. 2008;3:e2244. doi: 10.1371/journal.pone.0002244. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hooker CI, Verosky SC, Germine LT, Knight RT, D’Esposito M. Mentalizing about emotion and its relationship to empathy. Social Cognitive and Affective Neuroscience. 2008;3:204–17. doi: 10.1093/scan/nsn019. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hooker CI, Verosky SC, Germine LT, Knight RT, D’Esposito M. Neural activity during social signal perception correlates with self-reported empathy. Brain Research. 2010;1308:100–13. doi: 10.1016/j.brainres.2009.10.006. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Iacoboni M. Neural mechanisms of imitation. Current Opinion in Neurobiology. 2005;15:632–7. doi: 10.1016/j.conb.2005.10.010. [DOI] [PubMed] [Google Scholar]
- Iacoboni M, Dapretto M. The mirror neuron system and the consequences of its dysfunction. Natural Review of Neurosciences. 2006;7:942–51. doi: 10.1038/nrn2024. [DOI] [PubMed] [Google Scholar]
- Iacoboni M, Molnar-Szakacs I, Gallese V, Buccino G, Mazziotta JC, Rizzolatti G. Grasping the intentions of others with one's own mirror neuron system. PLoS Biology. 2005;3:e79. doi: 10.1371/journal.pbio.0030079. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Iacoboni M, Woods RP, Brass M, Bekkering H, Mazziotta JC, Rizzolatti G. Cortical mechanisms of human imitation. Science. 1999;286:2526–8. doi: 10.1126/science.286.5449.2526. [DOI] [PubMed] [Google Scholar]
- Iidaka T, Matsumoto A, Haneda K, Okada T, Sadato N. Hemodynamic and electrophysiological relationship involved in human face processing: evidence from a combined fMRI-ERP study. Brain and Cogniton. 2006;60:176–86. doi: 10.1016/j.bandc.2005.11.004. [DOI] [PubMed] [Google Scholar]
- Jabbi M, Keysers C. Inferior frontal gyrus activity triggers anterior insula response to emotional facial expressions. Emotion. 2008;8:775–80. doi: 10.1037/a0014194. [DOI] [PubMed] [Google Scholar]
- Jabbi M, Swart M, Keysers C. Empathy for positive and negative emotions in the gustatory cortex. Neuroimage. 2007;34:1744–53. doi: 10.1016/j.neuroimage.2006.10.032. [DOI] [PubMed] [Google Scholar]
- Kanwisher N, McDermott J, Chun MM. The fusiform face area: a module in human extrastriate cortex specialized for face perception. Journal of Neurosciences. 1997;17:4302–11. doi: 10.1523/JNEUROSCI.17-11-04302.1997. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kaplan JT, Iacoboni M. Getting a grip on other minds: Mirror neurons, intention understanding, and cognitive empathy. Social Neurosciences. 2006;1:9. doi: 10.1080/17470910600985605. [DOI] [PubMed] [Google Scholar]
- Kramer UM, Mohammadi B, Donamayor N, Samii A, Munte TF. Emotional and cognitive aspects of empathy and their relation to social cognition–an fMRI-study. Brain Research. 2010;1311:110–20. doi: 10.1016/j.brainres.2009.11.043. [DOI] [PubMed] [Google Scholar]
- Lamm C, Batson CD, Decety J. The neural substrate of human empathy: effects of perspective-taking and cognitive appraisal. Journal of Cognitive Neurosciences. 2007a;19:42–58. doi: 10.1162/jocn.2007.19.1.42. [DOI] [PubMed] [Google Scholar]
- Lamm C, Nusbaum HC, Meltzoff AN, Decety J. What are you feeling? Using functional magnetic resonance imaging to assess the modulation of sensory and affective responses during empathy for pain. PLoS ONE. 2007b;2:e1292. doi: 10.1371/journal.pone.0001292. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lee TW, Josephs O, Dolan RJ, Critchley HD. Imitating expressions: emotion-specific neural substrates in facial mimicry. Social Cognitive and Affective Neuroscience. 2006;1:122–35. doi: 10.1093/scan/nsl012. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mathur VA, Harada T, Lipke T, Chiao JY. Neural basis of extraordinary empathy and altruistic motivation. Neuroimage. 2010;51:1468–75. doi: 10.1016/j.neuroimage.2010.03.025. [DOI] [PubMed] [Google Scholar]
- Matsumuto D, Ekman P. Japanese and Caucasian Facial Expressions of Emotion (JACFEE) and Neutral Faces (JACNeuF) San Francisco: University of California, San Francisco; 1988. [Google Scholar]
- Morris JS, Frith CD, Perrett DI, et al. A differential neural response in the human amygdala to fearful and happy facial expressions. Nature. 1996;383:812–5. doi: 10.1038/383812a0. [DOI] [PubMed] [Google Scholar]
- Nichols T, Hayasaka S. Controlling the familywise error rate in functional neuroimaging: a comparative review. Statistical Methods in Medical Research. 2003;12:419–46. doi: 10.1191/0962280203sm341ra. [DOI] [PubMed] [Google Scholar]
- Nomi JS, Scherfeld D, Friederichs S, et al. On the neural networks of empathy: A principal component analysis of an fMRI study. Behavioural Brain Function. 2008;4:41. doi: 10.1186/1744-9081-4-41. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nummenmaa L, Hirvonen J, Parkkola R, Hietanen JK. Is emotional contagion special? An fMRI study on neural systems for affective and cognitive empathy. Neuroimage. 2008;43:571–80. doi: 10.1016/j.neuroimage.2008.08.014. [DOI] [PubMed] [Google Scholar]
- Ochsner KN, Knierim K, Ludlow DH, et al. Reflecting upon feelings: an fMRI study of neural systems supporting the attribution of emotion to self and other. Journal of Cognitive Neurosciences. 2004;16:1746–72. doi: 10.1162/0898929042947829. [DOI] [PubMed] [Google Scholar]
- Phillips ML, Young AW, Senior C, et al. A specific neural substrate for perceiving facial expressions of disgust. Nature. 1997;389:495–8. doi: 10.1038/39051. [DOI] [PubMed] [Google Scholar]
- Preston SD, de Waal FB. Empathy: Its ultimate and proximate bases. Behavioural Brain Sciences. 2002;25:1–20. doi: 10.1017/s0140525x02000018. [DOI] [PubMed] [Google Scholar]
- Rizzolatti G, Craighero L. The mirror-neuron system. Annual Revew of Neurosciences. 2004;27:169–92. doi: 10.1146/annurev.neuro.27.070203.144230. [DOI] [PubMed] [Google Scholar]
- Rizzolatti G, Fadiga L, Gallese V, Fogassi L. Premotor cortex and the recognition of motor actions. Brain Research and Cognitive Brain Research. 1996;3:131–41. doi: 10.1016/0926-6410(95)00038-0. [DOI] [PubMed] [Google Scholar]
- Rizzolatti G, Fogassi L, Gallese V. Neurophysiological mechanisms underlying the understanding and imitation of action. Natural Review of Neurosciences. 2001;2:661–70. doi: 10.1038/35090060. [DOI] [PubMed] [Google Scholar]
- Sprengelmeyer R, Rausch M, Eysel UT, Przuntek H. Neural structures associated with recognition of facial expressions of basic emotions. Proceedings of Biological Sciences. 1998;265:1927–31. doi: 10.1098/rspb.1998.0522. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vollm BA, Taylor AN, Richardson P, et al. Neuronal correlates of theory of mind and empathy: a functional magnetic resonance imaging study in a nonverbal task. Neuroimage. 2006;29:90–8. doi: 10.1016/j.neuroimage.2005.07.022. [DOI] [PubMed] [Google Scholar]
- Wicker B, Keysers C, Plailly J, Royet JP, Gallese V, Rizzolatti G. Both of us disgusted in My insula: the common neural basis of seeing and feeling disgust. Neuron. 2003;40:655–64. doi: 10.1016/s0896-6273(03)00679-2. [DOI] [PubMed] [Google Scholar]
- Xu X, Zuo X, Wang X, Han S. Do you feel my pain? Racial group membership modulates empathic neural responses. Journal of Neurosciences. 2009;29:8525–9. doi: 10.1523/JNEUROSCI.2418-09.2009. [DOI] [PMC free article] [PubMed] [Google Scholar]